Originally Posted by
750XL
The Boeing 787 could be a problem for this procedure as I believe it cannot start the engines without an external power source such as FEGP or GPU. Or maybe that was just peculiar to the 3rd prototype which we handled on a sales trip?
787 can start it's engines with the APU like any other aircraft can
Possibly the OP encountered a 787 with the APU u/s, in which case you obviously can't use an air cart for engine start and therefore need external electrical power ?